NL Writer C API: linear example #30

No suffixes, no names output

doc/source/components.rst

@@ -142,11 +142,18 @@ The library is zero-overhead: it does not store the model,
 nor does it require any intermediate objects to represent
 model information.
 
-The API is provided by classes `mp::NLSOL`, `mp::NLWriter2`,
-`mp::NLFeeder2`, `mp::SOLReader2`, `mp::SOLHandler2`.
-See
-`example <https://github.com/ampl/mp/blob/develop/nl-writer2/examples/nlsol_ex.cc>`_
-solving a small non-linear model.
+- **NL Writer C++ API** is provided by classes
+  `mp::NLSOL`, `mp::NLFeeder2`, `mp::SOLHandler2`.
+  See
+  `example <https://github.com/ampl/mp/blob/develop/nl-writer2/examples/cpp/nlsol_ex.cc>`_
+  solving a small non-linear model.
+
+- **NL Writer C API** is provided by structs
+  `NLSOL_C`, `NLFeeder2_C`, `SOLHandler2_C`.
+  *Currently only linear models are supported.*
+  See
+  `example <https://github.com/ampl/mp/blob/develop/nl-writer2/examples/c/nlsol_ex_c.c>`_
+  solving a small linear model.
 
 
 .. _recommended-driver-logic:

doc/source/index.rst

@@ -50,7 +50,7 @@ The documentation is divided in two sections:
   * :ref:`howto` illustrates how to get familiar with the framework and how to quickly obtain the
     boilerplate code necessary to develop a new solver driver
   * :ref:`components` shows the main components of the framework,
-    including NL reader and writer API
+    including NL reader and NL writer APIs
   * :ref:`howto-test` illustrates how to execute tests during development
   * :ref:`cppreference` contains the reference to all the classes in the framework 
 
@@ -73,7 +73,7 @@ Developer documentation
 -----------------------
 
 .. toctree::
-   :maxdepth: 2
+   :maxdepth: 3
 
    Developer docs <developers>
 

nl-writer2/examples/c/nlsol_ex_c.c

@@ -24,7 +24,7 @@ int main(int argc, const char* const* argv) {
            "where <solver> is ipopt, gurobi, minos, ...;\n"
            "binary/text is the NL format (default: binary.)\n"
            "Examples:\n"
-           "  <this_exe> highs \"\" text /tmp/stub\n"
+           "  <this_exe> highs \"writeprob=/tmp/stub.lp\" text /tmp/stub\n"
            "  <this_exe> gurobi \"mip:return_gap=1\"");
     exit(0);
   }

nl-writer2/examples/c/nlsol_ex_c_model.c

@@ -1,4 +1,5 @@
 #include <stdlib.h>
+#include <stdio.h>
 #include <math.h>
 #include <assert.h>
 
@@ -37,6 +38,10 @@ CAPIExample MakeCAPIExample_Linear_01() {
   static const SparseEntry obj_linpart[]
       = { {0, 13}, {1, 1.0} };
 
+  /// Solution
+  static double sol_dual[] = {NAN, NAN};
+  static double sol_primal[] = {NAN, NAN};
+
   CAPIExample result = {
     .n_var = 2,
     .n_var_int = 1,
@@ -59,7 +64,14 @@ CAPIExample MakeCAPIExample_Linear_01() {
     .obj_sense = 1,
     .obj_linpart = obj_linpart,
     .n_obj_nz = 2,
-    .obj_name = "TotalSum"
+    .obj_name = "TotalSum",
+
+    .binary_nl = 1,
+
+    .sol_dual_ = sol_dual,
+    .sol_primal_ = sol_primal,
+    .objno_ = -2,
+    .solve_code_ = -100
   };
   return result;
 }
@@ -73,5 +85,18 @@ void DestroyCAPIExample_Linear_01(CAPIExample* pEx) {
 }
 
 void PrintSolution_C(CAPIExample* pex, const char* stub) {
-  assert(0);
+  printf(
+        "\n     ********** SOLUTION (%s.sol) ***********\n",
+        stub);
+  printf("%s\n", "DUALS.");
+  for (int i=0; i<pex->n_con; ++i)
+    printf("   %10s = %.17g\n",
+           pex->con_name[i], pex->sol_dual_[i]);
+  printf("%s\n", "PRIMALS.");
+  for (int i=0; i<pex->n_con; ++i)
+    printf("      %7s = %.17g\n",
+           pex->var_name[i], pex->sol_primal_[i]);
+
+  printf("\nObjno used: %d, solve_result_num: %d\n",
+         pex->objno_, pex->solve_code_);
 }

nl-writer2/examples/c/nlsol_ex_c_model.h

@@ -100,6 +100,12 @@ typedef struct CAPIExample {
   /// Some technical stuff
   int binary_nl;
 
+  ///////////////////// SOLUTION //////////////////////
+  double* sol_dual_;
+  double* sol_primal_;
+  int objno_;
+  int solve_code_;
+
 } CAPIExample;
 
 /// Create linear example data

nl-writer2/examples/c/nlsol_ex_c_sol.c

@@ -2,14 +2,51 @@
 
 #include "nlsol_ex_c_sol.h"
 
+/// Declare, implementation in nlsol_ex_c_nl.c
+NLHeader_C CAPI_ex_Header(void* pex_void);
+
+void OnDualSolution(
+    void* p_user_data, int nvals, void* p_api_data) {
+  CAPIExample* pex = (CAPIExample*)p_user_data;
+  for (int i=0; i<nvals; ++i)
+    pex->sol_dual_[i] = NLW2_ReadSolVal(p_api_data);
+}
+
+void OnPrimalSolution(
+    void* p_user_data, int nvals, void* p_api_data) {
+  CAPIExample* pex = (CAPIExample*)p_user_data;
+  for (int i=0; i<nvals; ++i)
+    pex->sol_primal_[i] = NLW2_ReadSolVal(p_api_data);
+}
+
+void OnObjno(void* p_user_data, int on) {
+  CAPIExample* pex = (CAPIExample*)p_user_data;
+  pex->objno_  = on;
+}
+
+void OnSolveCode(void* p_user_data, int sc) {
+  CAPIExample* pex = (CAPIExample*)p_user_data;
+  pex->solve_code_ = sc;
+}
+
 SOLHandler2_C MakeSOLHandler2_C(CAPIExample* pex) {
-  SOLHandler2_C result;
+  SOLHandler2_C result
+      = NLW2_MakeSOLHandler2_C_Default();
 
   result.p_user_data_ = pex;
 
+  result.Header = CAPI_ex_Header;
+  // solve message: use default (print it)
+  // AMPL options: use default
+  result.OnDualSolution = OnDualSolution;
+  result.OnPrimalSolution = OnPrimalSolution;
+  result.OnObjno = OnObjno;
+  result.OnSolveCode = OnSolveCode;
+
   return result;
 }
 
 void DestroySOLHandler2_C(SOLHandler2_C* p) {
   p->p_user_data_ = NULL;
+  NLW2_DestroySOLHandler2_C_Default(p);
 }

nl-writer2/include/api/c/nl-feeder2-c-impl.h

@@ -200,64 +200,6 @@ class NLFeeder2_C_Impl
 
 
   ///////////////// 5. CONSTRAINT BOUNDS & COMPLEMENTARITY ///////
-  /// \rst
-  /// Algebraic constraint bounds (for a single constraint):
-  /// either range (lb, ub),
-  /// or complementarity info (k, cvar), when k>0.
-  ///
-  /// For a complementarity constraint to hold, if cvar is at
-  ///	its lower bound, then body >= 0; if cvar is at its upper
-  /// bound, then body <= 0;
-  ///	and if cvar is strictly between its bounds, then body = 0.
-  /// The integer k in a complementarity constraint line indicates
-  /// which bounds on cvar are finite: 1 and 3 imply a finite
-  /// lower bound; 2 and 3 imply a finite upper bound; 0 (which
-  ///	should not occur) would imply no finite bounds, i.e.,
-  /// body = 0 must always hold.
-  ///
-  /// Example:
-  ///
-  /// .. code-block:: ampl
-  ///
-  ///    ampl: var x; var y; var z;
-  ///	   ampl: s.t. Compl1: x+y >= 3 complements x-z <= 15;
-  ///	   ampl: s.t. Compl2: -2 <= 2*y+3*z <= 13 complements 6*z-2*x;
-  ///	   ampl: expand;
-  ///	   subject to Compl1:
-  ///					3 <= x + y
-  ///			 complements
-  ///					x - z <= 15;
-  ///
-  ///	   subject to Compl2:
-  ///					-2 <= 2*y + 3*z <= 13
-  ///			 complements
-  ///					-2*x + 6*z;
-  ///
-  ///	   ampl: solexpand;
-  ///	   Nonsquare complementarity system:
-  ///					4 complementarities including 2 equations
-  ///					5 variables
-  ///	   subject to Compl1.L:
-  ///					x + y + Compl1$cvar = 0;
-  ///
-  ///	   subject to Compl1.R:
-  ///					-15 + x - z <= 0
-  ///			 complements
-  ///					Compl1$cvar <= -3;
-  ///
-  ///	   subject to Compl2.L:
-  ///					2*y + 3*z - Compl2$cvar = 0;
-  ///
-  ///	   subject to Compl2.R:
-  ///					-2*x + 6*z
-  ///			 complements
-  ///					-2 <= Compl2$cvar <= 13;
-  ///
-  /// \endrst
-  struct AlgConRange {
-    double L{}, U{};
-    int k{0}, cvar{0};    // k>0 means complementarity to cvar
-  };
 
   /** Bounds/complementarity for all algebraic constraints
    *  (\a num_algebraic_cons).
@@ -293,7 +235,7 @@ class NLFeeder2_C_Impl
       bnd.U = bnd_c->U;
       crw.WriteAlgConRange(bnd);
     };
-    NLF().FeedVarBounds(NLF().p_user_data_, &crw_c);
+    NLF().FeedConBounds(NLF().p_user_data_, &crw_c);
   }
 
 
@@ -376,7 +318,13 @@ class NLFeeder2_C_Impl
    *          csw.Write(col_size[i]);
    */
   template <class ColSizeWriter>
-  void FeedColumnSizes(ColSizeWriter& ) { }
+  void FeedColumnSizes(ColSizeWriter& csw) {
+    assert(NLF().FeedColumnSizes);
+    std::function<void(int )> f = [&csw](int cs) {
+      csw.Write(cs);
+    };
+    NLF().FeedColumnSizes(NLF().p_user_data_, &f);
+  }
 
 
   ///////////////////// 12. INITIAL GUESSES /////////////////////

nl-writer2/include/api/c/nl-feeder2-c.h

@@ -20,7 +20,7 @@ extern "C" {
 void NLW2_WriteSparseDblEntry(
     void* p_api_data_, int index, double value);
 /// Write next variable's Lb, Ub
-void NLW2_WriteVarLbUb(void* p_api_data, int lb, int ub);
+void NLW2_WriteVarLbUb(void* p_api_data, double lb, double ub);
 /// Write next Jacobian column size
 void NLW2_WriteColSize(void* p_api_data, int sz);